Credit balance mechanism fob



CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES Filed April 22, 1948 I T. o. MEHAN April 24, 1951 '7 Sheets-Sheet 1 C u u I I IN VEN TOR.

p i 24, 1951 1-. o. MEHAN 2,550,581

CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES Filed April 22, 1948 v 7 Sheets-Sheet 2 I N VEN TOR. 1550mm: 0. Mzfiarz April 24, 1951 T. o. MEHAN 2,550,581

CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES Filed April 22, 1948 7 Shee'ts-Sheet 3 I INVENTOR- Zfioweas 0. Mgfian BY 7 v T. o. MEHAN 2,550,581

CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES April 24, 1951 '7 Sheets-Sheet 4 Filed April 22, 1948 INVENTOR. flfiovkaw 0. Meifiazn BY I Xhwi, m

T. o. MEHAN 2,550,581

CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES April 24, 1951 7 Sheets-Sheet 5 Filed April 22, 1948 m m m m April 24, 1951 T. o. MEHAN 5 5 CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES 7 Sheets-Sheet 6 Filed April 2.2, 1948 INVEN TOR.

8 T 150772036 0 j leiiczn April 24, 1951 r. 0. MEHAN 2,550,581

CREDIT BALANCE MECHANISM FOR CALCULATING MACHINES Filed April 22, 1948 7 Sheets-Sheet 7 fig. .9

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.m-vliz'w I llll lllaiilul INVENTOR. 168 176 .176 66 1.96 168 m 0 y fi Patented Apr. 24, 1951 CREDITBALANCE MECHANISM FOR CALCULATING MACHINES Thomas Mehan, Park Ridge, I 11., assignor to Victor AddingMachine Co., Chicago, I ll-,6; F.

poration of lllinois.

Application. April 22,1948, SerialNo; 22,526

Claims. 1

My. invention relates generally to adding and calculatingmachines, and more particularly to credit balance or overdraft mechanisms for machines of thistype.

As is well known in the art, calculating machines provided with subtract mechanisms are subject to erroneous operation when the total appearing in the accumulator in the machine is negative, unless some means is provided to add intothe accumulator the so called fugitive 1. Furthermore, it is desirable in such machines to indicate in one way or another that an overdraft has taken place, or in other words, that the machine contains a negative total. In machines provided with printing mechanism, this is customarily accomplished by printing a credit bal ance signal, such as C or Cr adjacent the subtotal or total.

In order that this entry ofth'e fugitive 1 is in the units pinion of the accumulator may be effected rapidly, as isrequired if'the machine is of the type which does not require a blank stroke to recondition the transfer mechanism for operation, it isvery desirable that the energy necessary for effecting the entry of the fugitive 1 be stored up and" thus bereadily available to effect such rapid operation.

It is therefore a primary object of the invention to provide an improved mechanism whereby the energy may be stored up for the rapid entry of" the fugitive 1, and-for the operation of the signal printing mechanism and associated parts.

A further object is to provide an improved mechanism for the entry of the fugitive 1, which is simple in construction, is reliable in operation, which may be readily used as an improvement onadding machines of well known'construction, and-- taken along the broken sectional line 33' of- Fig. 1, with portions of themechanism omitted;-

Fig. 4 is a left side elevationalview of the rearward portion of the machine with thecasin rem'oved,the view being on'theline 4-4 of Fig; 3;"

Fig. 5. is a right: side elevationrofportions of-the mechanism, taken: along theline 5 5.,of- Fig. 33'

Fig.- 6.:is a. fragmentarysectional: view, taken. along the. line 6.-Ji of. Fig. 3, showing. the ac-f cumulators in adding position;

Fig. 7: isaaview takenon the line 1.'! of Fig. 3, likewiseshowing the accumulator in, adding posi.-. tion;

Fig. 8-. is a. fragmentary sectionalsview, taken along the line 8.8 of Fig. 3;

Fig. 9is a fragmentary sectional view, taken along the brokenline 9.9 ofxFig. 1; showingthe: accumulators and the fugitive 1 entering. mechanism; and:

Fig. lilzisa. fragmentary sectional view, taken along the line. ll1+l0 of Fig. 3, with many parts omitted.

General description well be utilized in machines ofthe ten-key type.

Each of the-numeral-ke'ys' has a-keystem 30 which forms a stop for a- Vernier type slide 32 suit ably mounted forreciprocation beneath the ends of the key stems- 30; and provided with stop lugs 34 forcooperation with the ends of key stems-sit which have beendepressed; The slides 32; one for each denominational order of the machine, are respectivelyconnected to actuators 36 suitably mounted-forslidingmovement upon a pair-of fixed rods se-ane 3 9:- Each of the actuat0rs-isprovided w-itha pair of-racks-Ml and 4|, the racks 40=mshingwith segmental pin-ions 42 formed on type sectors 44; These sectors carry segr 'nental type bars 46, and are mounted for free" rotation on a shaft 43. A paper web 48 is fedr a r0 1v byi ab gmecham m. passi tially around a platen 50 which, to effect a printing operation, is swung toward the type on the type-bars 46'; an inked ribbon 52' being provided to efiecttheprinting impression.

The racks M onthe actuators 36 meshrespectivelywith segmental gears 54. Each ofthe-gears- 54 is fixedto a. hub 56 thehubs being rotatable upon a fixed sleeve 51 in which a shaft 58 is 3 rotatable. Each of the hubs 56 has an adding sector 60 freely pivoted thereon, this sector being normally urged counterclockwise relative to its associated segmental gear 54 by a tension spring 62, one end of which is secured to the segmental ear 60 and the other end of which is secured to a projecting arm on a disc 64 which is likewise fixed to its associated hub 56.

Transfer mechanism Each of the adding sectors 66 is normally held from counterclockwise (Fig. 1) movement under the influence of its associated spring 62 by the engagement of a hook shaped end 66 of a transfer pawl 68 with a lug 6'! projecting sidewardly from the sector 66, the transfer pawl 68 being pivoted upon a fixed shaft I and having forwardly projecting arms 12 engaged by a transfer latch I4. The latch 14 and the transfer pawl 68 are both biased to swing clockwise by a tension spring 16 connected between them.

Each of the adding sectors 60 is provided with a segmental gear I8 which is adapted to mesh with accumulator adding pinions 86 or the subtract pinions 82 which are intermeshed with the adding pinions. Each of the pinions 80 is provided with a transfer cam 8I fixed thereto, while each of the pinions 82 has a similar transfer cam 83 fixed thereto (Fig. 2), these cams being adapted to cooperate with cam projections 84 formed on the transfer pawls 68, each of the transfer cams 8| being adapted to engage the associated cam projection 84 as the pinion 80 rotates from 9 position to 0 position, while each of the cams 83 may be positioned to engage and trip its associated transfer pawl 68 as the pinion 80 moves from 0 to 9 position. This transfer mechanism does not per se form part of the present invention, except as the parts thereof are used in conjunction with the fugitive 1 inserting mechanism, this transfer mechanism being more fully disclosed in my prior Patent No. 2,411,050.

The accumulator pinions 86 are mounted on an accumulator shaft 86, while the pinions 82 are mounted for free rotation on a similar shaft 88, these shafts forming part of an accumulator frame 9?), the latter being shiftable from the position in which it is shown in Fig. 1, to the left so as to bring the pinions 82 instead of 80 into position for enmeshment with the adding sector gears 2'8. The accumulator frame 60 is also operated in a conventional manner at the required time in the operating cycle of the machine to swing the accumulator pinions 80 or 82 (depending upon whether adding, positive totals or sub totals, or on the other hand, whether subtract or negative total or subtotals are to be performed) into mesh with adding sector gears '18. The machine is equipped with the usual operating mechanism, either electric motor driven or hand operated, and is provided with the usual interlocks, controls, and control keys common to this type of machine, a illustrated and described in greater detail in the aforesaid Patent No. 2,411,050.

Fugitive 1 entering mechanism The accumulator is shifted from add to subtract position, and vice versa, by a lever 92 (Fig. 4) secured at 94 to the end of shaft 58, the depending arm of the lever 92 being provided with a fork 96 embracing a roller 98 rotatably mounted on the accumulator frame 96. A similar lever 200 (Fig. also secured to shaft 58, is slotted at 204 to embrace a roller 206 mounted on the other end of the accumulator frame 90. A link N30 has one end pivotally connected to a stud I62 secured near the lower end of the lever 92, while its other end is pivotally connected to an arm I0 3 forming part of a bail I06, the bail being mounted for pivotal movement upon a fixed shaft I63. The bail I66 has a second arm IIO which has a sidewardly extending lug II2 (Fig. 2).

As best shown in Figs. 1, 6, and 8, the lug II2 projects between opposed faces H4 and H5 of arm I I6 and I I'i, which are freely pivoted on the reduced diameter portion of a bushing II8 mounted for rotation on the shaft I08, as shown in Fig. 2a.

The arms IE6 and ill are urged to swing toward one another by a tension spring I20 (Fig. 2). A third arm i22 is preferably fixed to the bushing H8, the latter being rotatable upon the shaft I58, and the rearwardly extending portion of the arm I22 being provided with a notch I24. The arm I22 also has a sidewardly extending.

lug I26 which is positioned somewhere between.

the two stop faces I28 and I29 formed on the arms H5 and i '5, respectively.

The notch I24 normally embraces a sidewardly extending lug I30 on a depending arm of a transfer pawl i 32 associated with and adapted to be operated by the cams 3| or 83 of the highest denominational order accumulator pinions. The

transfer pawl I62 is normally urged to swing clockwise, as are the transfer pawls 68, by a suitably anchored tension spring 76.

A bail I33 is suitably mounted for rotation on;

the shaft 38, and has a sidewardly extending lug I86 on its lefthand arm I33, the lug I36 projecting into the space between the stop faces. H 3 and 555 of the arms H6 and III. The right-- hand arm I46 of the bail I34 extends rearwardly and carries a stud I42 which is normally posi-- tioned in a notch Mt formed in the transfer pawl I 36 associated with the adding sector 60 which operates the units order accumulator pinions thus forms a detent yieldable to hold the bail I34 and connected parts in either of their ex treme positions.

A bellcrank arm I60 fits over the shaft I08 and.

has an opening I62 for the reception of the reduced diameter end portion of stud 48 so that in effect the bellcrank I60 forms a part of thebail I34 and moves therewith. The rearwardly extending arm of the bellcrank I66 is provided with a sidewardly projecting stud I64 which is normally positioned in an open end slot I66 formed in the forwardly extending portion of a slide I68.

The slide I68 (Fig. 5) has a pair of elongated slots I70, I'II, through which project studs I12 and H3, secured to an arm I74. The slide I68 has a sidewardly extending stud I16 which, when the slide is in a lowered position, is adapted to abut a sidewardly extending lug I78 forming. part of freely pivoted arm I80.

The slide I68 has a second stud I82 which part of a signal type carrier I86.

carrier is mounted for rotation upon the shaft 43 upon which the numeral type carriers aiid other signal carriers are -mounted. The type carrier I86 carries a segmental type bar I89 having a projecting face I90 to print the character C to indicate, when a negative totaling or subtotaling operation is performed-that such totalor subtotal is of a negative or overdraft character.

The lever I14 is pivoted on a fixedstud I92 and is adapted to be swung counterclockwise (Fig. 5) whenever the total key I94 is swung forwardly from its normal position to effect the taking-ofa subtotal operation, or rearwardly from the normalposition to efiect a total taking operation. The connection between the stem of the total and subtotal key I94 and the lever I14 maybe of any suitable type, such as shown, for example, in said prior Patent No. 2,411,050.

Whenthe lever H4 is thus swung counterclockwise from the position shown in Fig. 5, a rearwardly projecting portion i96 of the slide I68 may engage a stud I98 projecting sidewardly from an auxiliary accumulator shift lever 266 pivoted on a rocking shaft '58. Such counterclockwise swingin of the lever I14 takes place without disengaging the stud I64 from the open end slot I66. Fig. 5 shows the parts in normal position during an adding operation. When the total and subtotal key is shifted in either direction to take a subtotal or total, the projection I96 at the lower end of the slide I63 engages the stud I98 and moves the lever 200 counterclockwise. The lower end of the lever 296 is provided with a notch 294 which embraces a roller 266 mounted on the accumulator frame 98. Levers 269 and 92, being fixed to the shaft 58, swing together and thus shift the accumulator frame 86 smoothly. Thus, if the accumulator frame 99 is not in position to have its adding pinions engage the adding sector gear 18, it will be shifted to such adding position by the engagement of the projection I96 with the stud I98, and the con sequent counterclockwise swinging movement of the levers 92 and 200.

On the other hand, as will appear more fully hereinafter, when the accumulator contains a negative total, the bellcrank I69 will have been swung clockwise from the position in which it is shown in Fig. 5, and thus move the slide I68 downwardly a distance corresponding to the length of the slots I1!) and I1 I. Such downward movement of the slide I68 will bring its stud I16 into position for engagement with the lug I18 on the arm I86. Therefore, when the arm I14 is swung counterclockwise by shifting the total and subtotal key I94 to either of its extreme positions, the stud I16 will engage the lug I18 and the lower end of the arm I89 will engage the upwardly extending arm of the auxiliary accumulator shift lever 200 and swing the latter clockwise, thereby shifting the accumulator 99 to bring the subtract pinions 82 into position for meshing engagement with the segmental gears 18. Such downward movement of the slide I68 also brings its rearward projection I96 below the stud I98 so that there is no interference with the clockwise swinging movement of the lever 200.

When the slide I68 moves downwardly (in the direction of slots I19, Ill), which occurs when the accumulator contains a negative balance, the stud I82 fixed to the slide I68 rides downwardly into the lower end of the elbow shaped slot-l84,

andthus is in position to move'thetypecarrier to one arm 228 ofa bail'229.

I when theslide I68-is-in its normaL upperposition,-as shown in Fig; 5, and the arm I14-is swung counterclockwise, the stud IB2-'movesupwardly in the upper portion of the elbow shaped slot I84, and since this movement is'about the pivot stud 192, such movement of the stud I82 does not change the position ofthe type carrier I86.

The typecarrier I86 hasa sidewardly extending stud 298 (Fig. 5) which projects into an open end' slot 2 Ifl formed at the 'end of an arm 2 I2, fixed to a suitably pivoted shaft 2. The shaft 2I4 extends transversely of the center section of'the'machine,asshown' idFigs. 3and 10. The left-hand'end (Fig. 3) of shaft 2 I4 has an'arm 2I6 fixed thereto (Fig. 4). The arm 2I6 overlies asidewardly extending stud 2I'8 formed on a rearwardly projecting arm 226 of a slide 222. The rearward end of the arm 2-I6 is provided withan open end slot which, by spreadingor narrowingthe slot with suitable tools, allows for adjustment of the contact of this arm'with-the stud 2I8. Thus the slide 222 is'moved downwardly whenever the amount inthe accumulatoris negative, this being accomplished through the previously described kinematic train comprising parts I34, I48, I60, I64, I'68,'I82, I86, 288, 2I2,

2I4, 2I6, 2I8, and 220.

The slide 222 is provided with elongated slots 224 and 225 which embrace a fixed stud- 226-and a stud 221, respectively. The-stud 221 is secured The bail 229' is pivoted by'means of a stud 239 whichextends through the arm 228 of this bail.

The slide'222 has a sidewardly projecting stud 232 which overlies the rearwardly extendingarm 234 of a lever 236 pivoted upon a stud-238 carried at the upper end of lever 92. The lever 236 is normally biased to move clockwise (Fig. 4) by a torsion spring 240 which is wound around the stud 238 and has one end anchored against a stud 242 fixed to the accumulator shifting lever 92.

The forwardl projecting arm of the lever 236 is provided with a hook portion 244 which in normal adding operations is adapted to be engaged by a stud 246 secured to a cam plate 248 fixed to the main shaft 258. It will thus be apparent that when the lever 236 is swung counterclockwise by downward movement of the slide 222 (as occurs when the amount in the-accumulator is negative), the hook portion 244 will be raised above or outwardly of the arcuate path of movement of the stud 246' and will thus'not be engaged'thereby, and the accumulator frame 99 will therefore not be returned to add position, but instead will remain in the subtract position, the accumulator being held in the subtract po sition by engagement of a stud 254, secured to the accumulator shift lever 92, in a notch 256 formed in a detent arm 258 pivoted on a stud 269 and biased to swing clockwise (Fig. 4) bya tenengaged by a; stud 212 which is carried vby a lever ping the tens transfer pawl 68.

214. The lower end of the lever 214 is provided with an open end slot 216 which embraces a stud 246. The lever 274 is pivoted on a stud 2'58. and, as is more fully disclosed in the aforesaid Patent No. 2,411,050, operates, through the lever 238, to slide the accumulator frame 98 forwardly to its subtract position.

Operation Assume that the accumulator contains a positive entry such, for example, as the positive amount and the operator depresses the amount key for 2, and conditions the machine for subtraction. Under these circumstances, the accumulator frame 98 will be shifted forwardly from the position in which it is shown in Figs. 1 and 4 by means of the customary controls, to bring the accumulator pinions 82 into position for meshing engagement with the adding segment gears I8. Upon operation of the machine to subtract the amount 2 from the amount 1, the accumulator pinion 82 will be rotated clockwise (Fig. 1, and the meshing accumulator pinions 88 rotated counterclockwise) to subtract the amount 2. In the course of this operation, as the units accumulator pinion 82 moves from the position to the 9 position, it will trip its transfer pawl 68 to cause the tens pinion 82 also to move from the 0 to the 9 position, thereby trip- Such successive tripping operations for the hundreds, thousands, ten thousands, etc., will takeplace rapidly until the accumulator pinion 82 for the highest denominational order rotates from 0 to 9 position, whereupon its transfer cam 83 will engage the cam projection 84 of the transfer pawl I32 to swing the latter counterclockwise (Fig. 2). In so doing, the lug I38 thereof will be disengaged from the notch I24.

It will be recalled that when the machine is conditioned for subtraction and the accumulator frame 98 is moved forwardly, the accumulator shift arm 92, by virtue of its connection with the bail I66 through link I06 (Fig. 2) will swing this bail clockwise on its shaft I66 to move the lug I12 to the left (Figs. 1 and 6), and thereby move the arm IIG clockwise. In so doing, the lug II2 leaves the face H of the arm Ill and engages the face I I4 of the arm I IS to swing the latter clockwise to further tension the spring I28, since the arm H1 is prevented from swinging clockwise by the lug I28 as long as the lug I36 is in the notch I24.

As will appear hereinafter, the energy thus stored up in the spring I26 is used to sheet the rapid entry of the fugitive 1.

Upon disengagement of the lug I38 from the notch I24 in the arm I22, due to the fact that the face I29 of the arm i'I'I presses against the lug I26, the arm I22 will be swung clockwise and the clockwise movement of the lug I26 will permit the arm II? to swing clockwise along with the lug I26, and such clockwise swinging movement of the arm II'I, due to its engagement with the lug I36 on bail I34, will also swing the latter clockwise. The clockwise movement of the bail I34 will raise the hook portion 66 of the transfer pawl I46 above the lug 61 of the adding segment 66 associated with the units order, the stud I42 moving out of the notch I44. When this occurs, the spring 62 will swing the adding segment 60 counterclockwise until the lug 67 bottoms in the hook portion 66 of the transfer pawl. Since the accumulator pinions 82 are in mesh with the segmental gear of the adding segments 66 at this time, the accumulator will have a unit entered therein.

At the conclusion of each cycle of operation, the transfer pawls 68, I32, and I46 are returned to and latched in normal position by the usual transfer mechanism restoring bail which includes a cross-rod 18 (Fig. 1).

The rod 15 is carried by the accumulator frame 96 which rocks on a pair of studs 284, 285 (Figs. 8 and 9) to move the accumulator pinions 80 or 82 into and out of mesh with the segmental gears 18. Thus when the accumulator pinions are swung out of mesh, the rod 15 engages the latches '14 of any of the carrier pawls I32, I46 which have been tripped, and restores them to latching position as shown in Fig. 1. This mechanism is more fully disclosed in my prior Patent No. 2,411,050.

At the beginning of each operating cycle, a rod 286 (Fig. 1) is rotated counterclockwise through a sufficient angle to cause a plate 289 secured thereto to engage the adjacent last tooth of each of the segmental gears which in the preceding cycle has been moved counterclockwise beyond its normal position in effecting a transfer. Such segmental gears are moved clockwise by the plate 268 to disengage the hook portions 66 of their transfer pawls 68 from lugs 61 on their associated segmental gears 66, and thereby permit their associated transfer pawls to be returned to their normal positions by their springs 16. The mechanism for rocking the rod 288 is likewise more fully disclosed in my said prior Patent No. 2,411,050.

If, while the accumulator contains a negative total or credit balance, a total or subtotal operation is performed, it will be understood that due to the shifting of the position of the bellcrank lever 186, the slide I68 will be moved to its lower position and its stud I16 will lie in front of the lug I18. Thus the swinging movement (counterclockwise) of lever I14, upon operation of the total ke I94, will cause the arm I86 to swing counterclockwise and swing the accumulator shift lever 260 clockwise to move the accumulator frame 88 forwardly and thereby bring the subtract pinions 62 into position for engagement with the adding gear segments 18. The downward movement of the slide I68 will also cause (through engagement of the roller I82 with the slot I84) the type carrier I86 to move counterclockwise to bring the C type I90 into printing position. By this means the correct negative total will be printed with the signal showing that the total was negative, this is, a credit balance or overdraft.

If the accumulator contains a negative total and an amount is added so as to cause the sum added into the accumulator to be positive, the units accumulator pinion 86, in moving from 9 to 0 position will cause a transfer to be efiected into the tens order, and since at or about this time the tens and all higher order accumulator pinions will be in 9 position, the transfer will be carried successively to the higher order accumulator pinions until the highest order accumulator pinion is moved from 9 to 0, whereupon the transfer pawl I32 associated with such highest order pinion will be tripped. Under these cir cumstances, the accumulator shift arm 92 will have been shifted rearwardly to shift the accumulator to add position, so that the bail I86 carrying lug H2 will be swung counterclockwise.

The lug 2 will therefore move the arm IIl counterclockwise (Fig. 6) and thereby apply addition'altensionto the spring I20. The arm I It will temporarily beheld stationary until, as above described, the transfer pawl I32 is' tripped, whereupon the arm I22 will be swung counterclockwise by the spring I acting through the arm IIS and the lug I26. Such counterclockwise swinging movement of the arm H5 also causes the bail I34 to be swung counterclockwise due to the engagement of the face II4 of arm I I6 with the lug I35 which forms part of the bail I34. The stud I48, with its roller i5i,-wi1l therefore shift from notch I52 to the notch Its in the spring actuated detent arm IM, and the transfer pawl I46 will therefore again be tripped to addthe fugitive 1 into the adding accumulator comprising the pinions 80. The bellcrank arm I-Bll will also be swung counterclockwise to raise the slide-I68 to "normal adding position so thatthe projection IB S-at the lower end of the slide will be in position to engage the stud I98. The machine will. then be in a condition to print a positive total.

If during any adding or subtracting operation, the capacity of the accumulator is exceeded, the fugitive 1 inserting mechanism will not operate effectively. This is because during adding operations the arm I is already in its farthest clockwise position and the spring I2il, although moving arm I22, cannot move arm I40 farther.

Similarly during subtracting operations, when the negative capacity of the machine is exceeded, the arm I40 will already have been moved to its farthest counterclockwise position, and hence the spring I20 cannot move it farther and the tripping of pawl I32 can have no effect.

It will be clear that at the completion of each operation the accumulator is in condition for the taking of a correct positive or negative total without the necessity of taking anyblank strokes. This is because the total taking mechanism is immediately conditioned for taking a positive or a negative total as soon as the fugitive 1 has been inserted. The power for the operation of the fugitive 1 inserting mechanism is derived from the energy stored up in spring I28, so that this mechanism may operate at any time, and it is held in the required position by the detent I54.

The fact that no blank stroke is required prior to the taking of either a positive or negative total or subtotal, is advantageous because of the greater simplicity and speed with which the machine may be operated.

While I have shown and described a preferred embodiment of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claims, to include within the scope of the invention all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

1. In an adding machine capable of performing subtracting operations and which has differentially movable actuators, the combination of an accumulator comprising a pair of parallel shafts, a plurality of similar pinions mounted for independent rotation on said shafts, the pinions on one shaft respectively meshing with those on the other shaft, a frame carrying said shafts, said frame being movable to bring the pinions on either shaft into meshing engagement with the actuators, a transfer cam on each of the pinions, transfer mechanisms associated with all except the highest denominational order pinions to effect transfers to the next higher order pinions, and means to effect a transfer from the highest order pinions to the lowest order pinions comprising: a pair of pivoted levers, a relatively strong spring tensioned between corresponding ends of the levers,'a single latch normally holding the levers from movement by the tensioned spring, said latch being positioned to be tripped by being engaged by the transfer cam on either of the highest order pinions, depending upon whichpinion is in mesh with its actuator, the latch being tripped when one of the highest order pinions moves from zero to nine position or when the other highest order pinion moves from' nine to zeroposition, an element moved by the tensioned-spring 'in-one" direction through one of the levers when the latch is tripped, a detent arm to hold the element in either of its extreme positions, means operated by said element to effect the addition of the fugitive 1 in the lowest order pinions when the said highest order pinion moves from zero to nine and to subtract the fugitive 1 in the lowest order pinions when said highest order pinion moves from nine to zero, said last named means operating immediately upon the aforesaid movement of the highest order pinions, and means to reset said levers and latch.

2. In a calculating machine of the type equipped for direct subtraction and having amount determining differential actuators, the combination of an accumulator comprising a pair of intermeshing pinions for each denominational order, means for selectively shifting one set of pinions into position for engagement with the actuators depending upon whether the operation to be performed is adding, taking a positive total, or subtracting, taking a negative total, transfer means operable to effect carrying operations from each order to the next higher order, and means to effect the entry of the fugitive 1 in the units order pinions comprising: transfer cams respectively connected to the highest orderv pinions, a pair of pivoted arms, a spring biased to swing said arms in opposite directions, means operated by the accumulator shifting means to tension the spring by swinging one of the arms away from the other, a latch positioned to be tripped by one of said transfer cams and normally holding said other arm against movement by said spring, an element engaged by said arms and arranged to be moved by the spring whenever the latch is tripped, means operated by said element immediately to effect the addition of a unit in the lowest denominational order pinion whenever said latch is tripped, and means operable during eachunachine cycle to reset said latch, arms, and element to their normal positions.

3. In a calculating machine having an accumulator comprising a plurality of pairs of intermeshing pinions, a transfer mechanism, toothed actuators, and means for shifting the accumulators into and out of mesh with the actuators; the combination of cams on the highest denominational order of pinions, a pair of pivoted arms, resilient means biased to swing said arms in opposite directions, a latch cooperating with one of said arms to hold it against movement by said resilient means, said latch being positioned for tripping by one of said cams when its associated pinion is in engagement with its actuator, thereby to release its cooperating arm for actua- 11' tion by the resilient means, mechanism operated by the arm immediately upon its release by the latch to effect the entry of 1 in the lowest order pinion which is at that time in mesh with its actuator, and means to reset the arm and its associated latch.

4. The combination set forth in claim 3 in which an operational control key is provided which when in one position conditions the machine for a subtracting operation, a negative balance indicating part, means operated by the control key when moved to subtract position partially to precondition said part for effective operation, and means operated by the one of said arms which is normally held by the latch to com pletely condition said part for efiective operation.

5. The combination set forth in claim 3 in which a resilient detent is provided to hold the one of said arms which is normally held by the latch in actuated position, and in which means are operated near the completion of an operating cycle of the machine to restore the latch and the arm associated therewith to their normal po- 5 sitions against the force applied by the resilient detent.

THOMAS O. MEHAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

